Electric motor, in particular radiator fan motor

ABSTRACT

An electric motor, in particular a radiator fan motor of a motor vehicle, has a rotor which is mounted such that it can rotate in relation to a stator, a motor mount which has an electronics compartment for accommodating a converter electronics system, and an electronics compartment cover. The electronics compartment cover has a peripheral sealing groove into which a peripheral edge of the electronics compartment engages by way of a corresponding sealing web in order to reliably seal off the electronics compartment.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of patent application Ser. No.14/206,187, filed Mar. 12, 2014; which was a continuation, under 35U.S.C. § 120, of International application No. PCT/EP2012/003578, filedAug. 24, 2012; the application also claims the priority, under 35 U.S.C.§ 119, of German patent application No. DE 10 2011 112 817.8, filed Sep.12, 2011; the prior applications are herewith incorporated by referencein their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to an electric motor, in particular a brushlesselectric motor with an inner rotor, preferably a radiator fan motor of amotor vehicle.

An electric motor of this type usually contains a rotor which is mountedrotatably with respect to a stationary stator. In the case of abrushless electric motor, the stator is often fitted with arotating-field winding, by which a magnetic rotating field is producedby applying an alternating current to the winding. The rotor arrangedwithin the substantially hollow-cylindrical stator is generally fittedwith permanent magnets which generate a rotor magnetic field alternatingwith the rotating field of the stator.

In the case of a brushless electric motor, the alternating currentprovided in order to feed the stator winding is usually generated by aconvertor (invertor). In the case of smaller electric motors, theconvertor is often accommodated together with an associated controlelectronics unit in an electronics compartment, which is integrated intothe motor housing. Here, the control electronics unit is to be protectedagainst moisture, which is why, in the case of such electric motors usedfor example as radiator fan motors in motor vehicles, comparatively highdemands are placed on the tightness of the electronics compartment.

SUMMARY OF THE INVENTION

The object of the invention is therefore to specify an electric motor ofthe aforementioned type, of which the electronics unit is reliablysealed with minimal outlay.

Accordingly, the electric motor, which is preferably brushless andconfigured as an inner rotor, contains a rotor which is mountedrotatably with respect to a stator, and contains a motor mount. Themotor mount forms or contains an electronics compartment foraccommodating a convertor electronics system. In addition to the passiveand active components, in particular such as a plurality of powersemiconductors which are connected in the form of a bridge circuit, theconverter electronics system contains a printed circuit board which isfitted, inter alia with the components.

An electronics compartment cover also referred to hereinafter as ahousing cover covers the electronics compartment in a sealing manner.For this purpose, the electronics compartment cover has a peripheralsealing groove and the motor mount, in the region of the electronicscompartment, has a sealing edge running around the electronicscompartment. The sealing edge is provided with a sealing web whichengages, in particular in a form-fitting manner, in the sealing grooveof the electronics compartment cover.

The sealing web protrudes upwardly in a lobe-like manner from theperipheral sealing edge and is integrally molded thereon, formingsealing shoulders on either side. The dimensions of the mount-sidesealing edge on the one hand and of the cover-side sealing groove on theother hand are selected in such a way that a filling gap for receiving asealing material remains between the sealing web and the sealing groove.The sealing material is preferably a sealing compound that becomesadhesive by heating.

When fitting the electronics compartment cover or housing cover, inorder to center the cover as precisely as possible and therefore ensurea filling gap that is as uniform as possible for the sealing compound,spacing pawls or nubs are molded into the peripheral sealing groove onthe cover side. Only a few spacing pawls or nubs provided at exposedlocations are required for a corresponding sufficient centering anduniform gap formation. These pawls or nubs are preferably integrallymolded on the inner side of the sealing groove, which is to say on thegroove wall facing the electronics compartment. The filling gap regionthat is formed between the opposed outer-side groove wall of thecover-side sealing groove and the sealing web thus remains free ofinterruptions. It is thus ensured that at least this filling gap regionin the joined state between the housing cover and the electronicscompartment is filled with an interruption-free and sufficientlyvoluminous length of the sealing material. A reliable seal between thehousing cover and the electronics compartment is thus produced in asimple manner.

In order to provide a further or alternative measure for centering, atleast for roughly centering, and fixing, at least roughly fixing, thehousing cover on the motor mount, fixing clamps are integrally molded onthe housing cover, preferably on opposite sides. These fixing clampspass over the ribs, which are provided on the motor mount and extendsuitably radially, in order to preferably lock together with the ribs.

In a suitable embodiment the stator is over-molded by a plastic casing.A particularly reliable and easily produced connection between the motormount and the stator is expediently achieved in that a number ofcaulking nubs are integrally formed on the plastic casing of the statorand pass through fixing openings provided on the motor mount. To jointhe motor mount and the stator or the plastic casing thereof, thecaulking nubs passing through the fixing openings are, for example,hot-caulked and thus deformed. Four caulking points of this type aresuitably provided between the substantially circular stator or theplastic casing thereof and the suitably relatively flat motor mountproduced as a cast part.

The sealing concept according to the invention of the electric motoradditionally or alternatively contains sealing elements that enable thewinding ends or connection ends of the stator-side rotating-fieldwinding formed from coils to be passed through into the electronicscompartment in a sealed manner. For this purpose, sealing elements areprovided that are preferably produced from a two-component plastic andthat contain a comparatively hard supporting component and acomparatively soft seal component as a one-piece component part.

In the assembled state, the sealing elements sit with the comparativelysoft seal component thereof in openings that are formed in the motormount in the region of the base of the electronics compartment. Thesesoft seal components of the sealing elements are formed suitably in themanner of a labyrinth seal.

The comparatively hard supporting components of the sealing elementsprotrude on the mount side of the motor mount facing away from thehousing cover and facing toward the stator. Here, the position of thesealing elements is selected in such a way that the comparatively hardsupporting components thereof are located axially above the stator-sideplastic casing. In order to position the sealing elements in a manneraligned with the stator-side plastic casing, receiving pockets areformed in the plastic casing, in which the comparatively hard supportingcomponents sit.

For a reliable positioning, fixing and/or stabilization, plug pins,preferably two plug pins, are integrally formed on each of thesupporting components and can be inserted into corresponding plugopenings in the plastic casing in the region of the receiving pockets,that is to say in the pocket bases thereof. Two openings in each of thehard supporting components of the sealing elements serve to pass throughtwo winding ends which exit from the soft seal components of the sealingelements and are contacted in the assembled state within the electronicscompartment with the convertor electronics system arranged there,preferably producing a delta connection of the coil windings orrotating-field windings.

For a particularly reliable sealing of the winding ends at the exitpoints thereof from the soft seal components, sealing sleeves areintegrally formed thereon and enclose the respective winding end in asealing manner.

The sealing concept for the winding ends of the rotating-field windingor coils thereof by the sealing elements constitutes an invention initself. The electric motor in this regard, in particular as a radiatorfan motor for a motor vehicle, contains a rotor which is mountedrotatably with respect to a stator, and contains a motor mountcontaining an electronics compartment for a convertor electronics systemand having openings within the electronics compartment. The winding endsof a stator-side rotating-field winding are introduced into theelectronics compartment via sealing elements. The sealing elements,which preferably consist of a two-component plastic, each have acomparatively soft seal component and a comparatively hard supportingcomponent, wherein the seal element sits in a sealing manner via thesoft seal component thereof, which is suitably formed as a labyrinthseal, in the respective opening in the motor mount or electronicscompartment.

In an advantageous embodiment of this electric motor the stator isover-molded by a plastic casing, in which receiving pockets are molded,in which the hard supporting component of the respective sealing elementsits. The further embodiments of the seal elements also apply similarlyto this electric motor according to the invention.

The joint between the motor mount and the stator over-molded by theplastic casing, the joint being provided by the caulking nubs integrallymolded on the plastic casing, also constitutes an independent invention.The electric motor in this regard, in particular as a radiator fan motorfor a motor vehicle, contains a rotor which is mounted rotatably withrespect to a stator, and containing motor mount, wherein the stator isover-molded by a plastic casing. At least one caulking nub, preferably aplurality of caulking nubs, are integrally molded on the plastic casingand pass through the corresponding caulking or fixing openings in themotor mount and can be deformed, preferably can be hot-formed, in orderto join the motor mount and the stator.

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention is illustrated and described herein as embodiedin an electric motor, in particular a radiator fan motor, it isnevertheless not intended to be limited to the details shown, sincevarious modifications and structural changes may be made therein withoutdeparting from the spirit of the invention and within the scope andrange of equivalents of the claims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof will be bestunderstood from the following description of specific embodiments whenread in connection with the accompanying drawings (examples).

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a diagrammatic, exploded, perspective view of a radiator fanfor a motor vehicle with its own cooled, brushless inner rotor motorwith integrated convertor electronics system according to the invention;

FIG. 2 is a perspective view from a connection side of the motoraccording to FIG. 1;

FIG. 3 is a plan view of the motor according to FIG. 1 with removedelectronics compartment cover (housing cover);

FIG. 4 is a perspective view of the electronics compartment cover froman inner side thereof;

FIG. 5 is a perspective view of a motor mount of the electric motor,looking into the electronics compartment without convertor electronicssystem;

FIG. 6 is a perspective view of detail VI shown in FIG. 4 on an enlargedscale with a fixing clamp integrally molded on a housing cover and witha spacing pawl in a cover sealing groove;

FIG. 7 is a sectional view of a centering joint between the housingcover and the edge of the electronics compartment of the motor mount;

FIG. 8 is a perspective view according to FIG. 2 of a detent connectionbetween the cover-side fixing clamp and a mount-side rib;

FIG. 9 is a perspective view of the stator of the motor, the statorbeing wound by coils of a rotating-field winding, with an over-moldedplastic casing with caulking nubs and with winding ends guided viasealing elements, according to FIG. 8 the effect of the rotor being thatof inherent cooling of the motor in the event of rotor rotation againstthe reference rotation direction;

FIG. 10 is a perspective view according to FIG. 5, of the motor mountjoined to the over-molded stator, as viewed from a caulking point;

FIG. 11 is a perspective view of the rotating-field winding with windingends thereof guided through sealing elements;

FIG. 12 is a perspective view of the winding and a sealing elementarrangement according to FIG. 11 with a fitted motor mount; and

FIG. 13 is a perspective view of the arrangement according to FIG. 11inclusive of stator laminated core.

DETAILED DESCRIPTION OF THE INVENTION

Parts and dimensions corresponding to one another are always provided inall figures with like reference signs. Referring now to the figures ofthe drawings in detail and first, particularly to FIG. 1 thereof, thereis shown an exploded view of a fan 1 for a radiator of a motor vehicle.The fan 1 contains an impeller 2 with a central cap 3, around the outercircumference of which (only illustrated in part) air guide vanes 4 areuniformly distributed. The fan 1 further contains an electric motor 5,also referred to as a fan motor, by which the impeller 2 is driven inrotation.

The motor 5 is formed substantially by a stator 6, on which athree-phase rotating-field winding 7 is wound in the form of coils. Themotor 5 further contains a permanently excited rotor 8, which is mountedrotatably about a motor axis 9 within the stator 6. In order to mountthe rotor 8, the motor 5 contains two rolling bearings 10 and 11, whichact on the rotor 8 from axially opposed sides. The axial play of therotor 8 between the two rolling bearings 10 and 11 is spring-loaded hereby a spring washer 12.

The motor 5 further contains an approximately disk-shaped motor mount13. An electronics compartment 14 is introduced into the motor mount 13at an end face facing away from the impeller 2, a convertor electronicssystem 15 being inserted into the electronics compartment. In order totightly close the electronics compartment 14, the motor 5 contains anelectronics compartment cover 16, also referred to hereinafter as ahousing cover.

The rotor 8 is formed (in a manner not illustrated in greater detail) bya laminated core, into which permanent magnets for generating anexciting field are inserted, wherein the laminated core is over-moldedtogether with the inserted permanent magnets by a plastic casing.Similarly, the stator 6 also contains a laminated core that isover-molded by a plastic casing.

The motor mount 13 is formed in particular by a one-piece die-cast partmade of aluminum. The electronics compartment cover 16 is preferably aninjection-molded part made of plastic.

On its front face, the rotor 8 is provided with four screw bosses 18, bywhich the rotor 8 is screwed to the impeller 2 in the assembled state.The motor 5 and therefore the entire fan 1 is fastened to the vehiclevia the motor mount 13, which for this purpose is provided with threescrew tabs 19 protruding from its outer circumference. The motor 5 is abrushless inherently cooled inner rotor motor.

In the assembled state of the motor 5 shown in FIG. 2 the stator 6 isfixedly attached on a front face of the motor mount 13. The rotor 8 isinserted into the stator 6 over-molded by the plastic casing 20, whereinthe rotor 8 is flanked on both axial sides by one of the two rollingbearings 10 and 11. The rolling bearings 10 and 11 are mounted here in amanner not illustrated in greater detail on an axial pin which is inturn fastened to the motor mount 13.

FIG. 3 shows the motor 5 with a removed electronics compartment cover16, looking into the electronics compartment 14 with convertorelectronics system 15 arranged therein. Supply lines (positive andnegative pole or ground pole) 21 a and sensor or data lines 21 b of aconnection cable 21 are led to or contacted with the convertorelectronics system. The electronics compartment 14 is enclosed by aperipheral, closed sealing or joining edge 22. Outside the electronicscompartment 14, the motor mount 13 has clamping ribs 23 runningsubstantially radially. These ribs are located substantially on oppositesides of the electronics compartment 14. Fixing or caulking openings 24are located at a number of positions distributed over the circumferenceof the motor mount 13.

Whereas FIG. 4 shows the electronics compartment cover or housing cover16 with a view of the inner side thereof, FIG. 5 shows a perspectiveillustration of the motor mount 13 with the electronics compartment 14thereof enclosed by the sealing edge 22, without convertor electronicssystem 15. A raised sealing web 25 is integrally molded on the sealingedge 22 of the electronics compartment 14 and is likewise closedperipherally, the contour of the sealing web as well as that of theelectronics compartment edge 22 and the shoulder-like contour thereof atthe transition to the sealing web 25 being visible comparatively clearlyin FIG. 7.

In the joined state of the electronics compartment cover 16 and themotor mount 13, the mount-side sealing web 25 engages with acorresponding sealing groove 26 in the housing cover 15 (FIG. 7). Thedimensions of the mount-side sealing web 25 and of the cover-sidesealing groove 26 are matched to one another in such a way that afilling gap 27 for a sealing material (not shown) remains therebetween.

A number of spacing pawls 28 are integrally formed on the inner side ofthe sealing groove 26, specifically on the groove wall 26 a thereoffacing the electronics compartment 14, and protrude into the sealinggroove 26. In the joined state, the mount-side sealing web 25 bearsagainst the spacing pawl 28 at the accordingly exposed locations. Thesespacing pawls 28 result in a reliable centering when the housing cover16 is fitted onto the edge 24 of the electronics compartment 14, in sucha way that a correspondingly uniform filling gap 27 for the sealingcompound, which for example becomes adhesive by heating, remains alongthe peripherally closed sealing edge 24 of the electronics compartment14 between the mount-side sealing web 25 and the cover-side sealinggroove 26 in the joined state. In particular, an uninterrupted, that isto say also pawl-free, filling gap region 27 a is produced on the grooveside opposite the spacing pawl 28, that is to say between the outer-sidegroove wall 26 b and the sealing web 25. The sealing compound oradhesive compound filled into the filling gap region thus provides aperipherally practically constant sealing or adhesive volume for aparticularly reliable seal of the electronics compartment 14 and fixedadhesive join between the housing cover 16 and the motor mount 13.

At least one fixing or latching clip 29 is integrally formed on theelectronics compartment cover 16 for roughly fixing and/or roughlypositioning. As can be seen from FIG. 4, two fixing clamps 29 that arediametrically opposed where possible are provided. As can be seen fromFIG. 2 and comparatively clearly from FIG. 8, the fixing clamps 29 arelocked with corresponding clamping ribs 23 of the motor mount 13.

For this purpose, the respective fixing clamp 29 is formed in accordancewith FIG. 6 in a substantially U-shaped manner with two clampingbranches 29 a and 29 b, which each carry, at the end, a detent pawl 29 cand 29 d respectively. The detent pawls 29 c, 29 d are directed inwardlyand preferably extend toward one another at the same height. In thelocked state, the two detent pawls 29 c and 29 d engage around thecorresponding clamping rib 23 of the motor mount 13.

FIG. 9 shows the stator 6, on which the rotating-field winding 7 iswound and which is over-molded by the plastic casing 20. In order toconnect the stator 6 to the motor mount 13, caulking nubs 30 raised inthe direction of the motor mount 13 are integrally formed on the plasticcasing 20 of the stator 6 and pass in the joined state through thecorresponding caulking or fixing openings 24 in the motor mount 13. Thejoined state is illustrated in FIG. 10. The caulking nubs 30 are thencaulked, for example hot-formed.

In the joined state, the pairs 31 of winding ends 31 a, 31 b of therotating-field winding 7 preferably protrude in each case in the samequadrant of the circular stator 6 into the electronics compartment 14,where they are bent substantially at right angles in a manner runningradially inwardly. Three such pairs 31 of winding ends 31 a, 31 b areprovided. When joined so as to contact the convertor electronics system15, the winding ends 31 a, 31 b are preferably connected in a deltaconnection of the coils 7 a forming the rotating-field winding 7.

The winding end pairs 31 of the rotating-field winding 7 are introducedinto the electronics compartment 14 via openings 32 in the motor mount13 in a manner reliably sealed by sealing elements 33. Each of thesealing elements 33 consists of a two-component plastic with acomparatively soft sealing component 33 a and with a comparatively hardsupporting component 33 b formed in one piece with the comparativelysoft sealing component.

As can be seen comparatively clearly from FIG. 11, the comparativelysoft seal component 33 a of the respective sealing element 33 is formedin the manner of a labyrinth seal with outer-side beads arranged axiallyin succession. The comparatively hard supporting component 33 b formedin one piece with the soft seal component 33 a carries integrally moldedplug pins 34 on the base side, that is to say on the underside facingaway from the soft seal component 33 a. Here, two such plug pins 34 areprovided per seal element 33.

As can be seen from FIG. 12, the hard supporting component 33 b of therespective sealing element 33 protrudes from the motor mount 13 on themount side facing the stator 6 or the rotating-field winding 7. In themeantime, the soft seal component 33 a of the corresponding sealingelement 33 sits in a sealing manner in the mount-side opening 32 in themotor mount 13.

As can be seen from FIG. 13, the comparatively hard supporting component33 b of the respective sealing element 33 sits in the assembled state ina receiving pocket 35 molded into the plastic casing 20 of the stator 6.Base-side plug openings 36 are formed in the receiving pockets 35, thecorresponding plug pins 34 of the sealing elements 33 plugging into theplug openings.

As can be seen comparatively clearly from FIGS. 11 and 13, a sealingsleeve 33 c or 33 d is molded integrally on the soft seal component 33 aof the respective sealing element 33 for each of the winding ends 31 aand 31 b respectively of the winding end pair 31 and encases therespective winding end 31 a or 31 b respectively in a sealing manner. Inaddition, openings 37 for passing the winding ends 31 a, 31 b throughthe respective seal element 33 are formed in the hard supportingcomponent 33 b of the seal element.

The invention is not limited to the above-described exemplaryembodiments. Rather, other variants of the invention can also be derivedby a person skilled in the art without departing from the subject of theinvention. In particular, all individual features described inconjunction with the various exemplary embodiments can be combineddifferently without departing from the subject of the invention.

The sealing concept for the winding ends 31, 31 a, 31 b of therotating-field winding 7 or coils 7 a thereof by the sealing elements 33is thus already inventive per se and therefore constitutes its owninvention.

The electric motor 5 in this regard, in particular formed as a radiatorfan motor for a motor vehicle, contains a rotor 8 which is mountedrotatably with respect to a stator 6, and contains a motor mount 13having an electronics compartment 14 for a convertor electronics system15 and having openings 32 within the electronics compartment 14. Thewinding ends 31, 31 a, 31 b of a stator-side rotating-field winding 7are introduced via sealing elements 33 into the electronics compartment14. The seal elements 13, preferably consisting of a two-componentplastic, each have a comparatively soft seal component 33 a and acomparatively hard supporting component 33 b, and wherein the respectiveseal element 33 sits in a sealing manner via the soft seal component 33a thereof, which is suitably formed as a labyrinth seal, in therespective opening 32 in the motor mount 13 or electronics compartment14.

In an advantageous embodiment of this electric motor 5 the stator 6 isover-molded by a plastic casing 20, in which receiving pockets 35 aremolded, in which the hard supporting component 33 b of the respectivesealing element 33 sits. The further embodiments of the sealing elements33 also apply similarly to the electric motor 5 according to theinvention.

The joint between the motor mount 13 and the stator 6 over-molded by theplastic casing 20, the joint being provided by the caulking nubs 30integrally molded on the plastic casing 20, also constitutes anindependent invention.

The electric motor 5 in this regard, in particular formed as a radiatorfan motor for a motor vehicle, contains a rotor 8 which is mountedrotatably with respect to a stator 6, and contains a motor mount 13. Thestator 6 is over-molded by a plastic casing 20, on which at least onecaulking nub, preferably a plurality of caulking nubs 30, are integrallymolded and pass through the corresponding caulking or fixing openings 24in the motor mount 13 and can be deformed, preferably can be hot-formed,in order to join the motor mount 13 and the stator 6.

1. An electric motor, comprising: a stator and a rotor rotatably mountedwith respect to said stator; a motor mount formed with an electronicscompartment for accommodating a convertor electronics system, saidelectronics compartment having a peripheral edge; an electronicscompartment cover formed with a peripheral sealing groove engaged bysaid peripheral edge of the electronics compartment via a correspondingsealing web; said motor mount being a one-piece die-cast part ofaluminum and having radially extending clamping ribs outside of saidelectronics compartment on an upper side facing said electronicscompartment cover; wherein: a filling gap is formed between saidperipheral sealing groove on a cover side and said corresponding sealingweb of said electronics compartment, and a sealing compound forming asealing material that becomes adhesive by heating is inserted into saidfilling gap; and at least one fixing clamp is integrally formed on saidelectronics compartment cover, said fixing clamp passing over one ofsaid clamping ribs of said motor mount at least for roughly fixing saidelectronics compartment cover on said motor mount.
 2. The electric motoraccording to claim 1 configured as a radiator fan motor of a motorvehicle.
 3. The electric motor according to claim 1, which comprises twofixing clamps, which are integrally formed on said electronicscompartment cover on opposite sides, each of said fixing clamps passingover one of said clamping rib on said motor mount.
 4. The electric motoraccording to claim 1, which comprises a plurality of spacing pawls forbearing against the corresponding sealing web of the electronicscompartment molded into said peripheral sealing groove on a cover side.5. The electric motor according to claim 1, wherein the respectivefixing clamp is substantially U-shaped with two clamping branches, whicheach carry, at an end thereof, a detent pawl directed inwardly, andwherein said detent pawls engage around the corresponding said clampingrib of said motor mount in a locked state.